The Blood Rheology of Man and Various Animal Species

Abstract

SUMMARYA comparative study has been made of the blood rheology, and its component factors, in horse, sheep, cattle, goat, camel, pig, dog, rabbit and man. The erythrocyte flexibility of horse red cells is high relative to man, that of pig, dog, camel and rabbit comparable, but less flexible, and sheep, cattle and goat relatively inflexible. The erythrocyte flexibility of horse, sheep, cattle and goats does not vary with the plasma fibrinogen level, as occurs with human and rabbit cells. Washing erythrocytes and then suspending them in isotonic saline makes the erythrocytes of all species relatively inflexible. There is a factor in horse plasma, which is not fibrinogen, that makes horse and human erythrocytes suspended in it very flexible. The blood viscosity of all species is comparable at high shear rates (230 s-') due to the shape of the cells compensating for their flexibility. The variations of blood viscosity at low shear rates (11-5 s-1) were also found to depend on the erythrocyte flexibility, and only influenced indirectly by the fibrinogen concentration. There is no significant effect of temperature on the erythrocyte flexibility of horse, sheep, cattle, goat and a small number of human subjects. This is reflected in the way the viscosity of these bloods varies with temperature.

Scaling laws for capillary vessels of mammals at rest and in exercise

“…For a number of identical parallel vessels N C , the velocity V C is equal to the total average blood flow Q B divided by the net sectional area N C pR 2 C so that the relation is DP = 8mL C Q B /N C pR 4 C . The viscosity of the blood may be assumed to be independent of mammal size, in agreement with laboratory measurements of Amin & Sirs (1985) on the blood of mammals ranging in size from rabbit to horse. The proportional relation for the condition of size-independent driving pressure DP is then expressible in the form of the similarity relation DP~L C Q B /N C R 4 C~M 0 , where the symbol~denotes proportionality under change of scale and M denotes mammal mass.…”

Direct Tracking of Particles and Quantification of Margination in Blood Flow

“…In unwashed blood, such particle adhesion to the bottom of the channel made particle tracking difficult or impossible (see Supporting Materials and Methods). Furthermore, the washing of bovine blood and its resuspension in phosphate-buffered saline resulted in bovine RBCs with elasticities similar to those of human RBCs (42). Spherical, fluorescent polystyrene particles (0.53, 0.84, and 2.11 mm in diameter) were used as model particles in the experimental system (Spherotech, Lake Forest, IL).…”

The Structure and Function of a Red Blood Cell in Health and Critical Conditions

“…Практически не агрегируют эритроциты сморщенные и уплотненные, после пребывания в гипертоническом растворе [57]; незначительна агрегация овалоцитов in vitro [58]. Однако эхиноцитоз не только не препятствует формированию агрега тов, но сопровождается формированием агрегатов повышен ной прочности [59].…”